Submitted to: Journal of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 3/15/2004
Publication Date: 3/15/2004
Citation: Panetta, D., Powers, W.J., Xin, H., Kerr, B.J., Lorimor, J.C. 2004. Nitrogen excretion and ammonia emissions from pigs fed reduced crude protein diets. Journal of Animal Science. 82(2):84. Interpretive Summary:
Technical Abstract: Two experiments were conducted to quantify the effects of dietary strategies on NH3 emissions of growing-finishing pigs. In Exp 1, nine pigs (initial BW = 47 kg) were fed corn-soybean meal diets fortified with no amino acids (17.4% CP), Lys (17.0% CP), or Lys, Met, Thr, and Trp (14.5% CP). In Exp 2, nine pigs (initial BW = 41 kg) were fed the Lys diet with 0, 62.5 or 125 ppm of yucca extract (Alltech®). Two gilts and one barrow were allocated to each of three indirect calorimeters. Four 1-wk feeding periods, with new diets assigned weekly, consisted of a 4-d dietary adjustment followed by 72 h of continuous NH3 measurement from chamber exhaust. Pigs and feed refusals were weighed, urine and fecal samples collected, and manure pits cleaned after each period. Feed intake (FI) and gain (ADG) were measured each period. Diets, urine, and fecal samples were analyzed for TKN and NH3-N concentration. In Exp 1 and 2, diet had no effect on FI, ADG, or feed efficiency (P > 0.05). In Exp 1, TKN in feces (3.97, 3.93, 3.72%; P < 0.001) and urine (1.10, 0.94, 0.93%, P = 0.04) decreased with decreasing dietary CP. Fecal NH3-N decreased with decreasing dietary CP (0.47, 0.47, 0.42%, P = 0.01) while urine NH3-N increased (0.10, 0.10, 0.20%, P < 0.001). Weekly NH3-N emissions were 22.25, 19.22, and 11.85 g/chamber (± 8.87 SEM; P > 0.05). The fraction of excreted TKN emitted as NH3 during the week was 1.68, 1.52, and 0.91% (± 0.60 SEM; P >0.05). In Exp 2, there was a significant linear response to increasing yucca content for urine NH3-N (0.14, 0.13, 0.11%, P = 0.05). Fecal TKN (3.59% ± 0.06 SEM), fecal NH3-N (0.48% ± 0.03 SEM), urine TKN (0.94% ± 0.07 SEM), NH3-N emissions (12.02 g ± 2.81 SEM) and the fraction of excreted TKN emitted as NH3 during the week (1.20% ± 0.24 SEM) were not affected by diet (P>0.05). Reducing diet CP and including NH3-binding agents can be effective in reducing N content of excretions and NH3 emissions. Less than 2% of excreted N was volatilized as NH3 during the collection period.